1. Field of the Invention
This invention relates generally to image capture techniques, and more particularly to enhancing a captured image of a scene by adjustments enabled through depth information.
2. Description of the Related Art
Image capture devices, whether cameras or video based devices, typically have a limited contrast ratio, which is a measure of the difference between the darkest and lightest parts of a scene. One exemplary scene may include a person in the shade and the background having bright sunlight. When the background of this scene is exposed correctly for the image capture device, there is little or no detail in the shaded person's face.
Auto-exposure and auto-gain features are commonly used to set brightness levels for the capture device. These features tend to take the entire scene and average it to apply a certain exposure or gain setting. While the averaging may work well for a scene having a great deal of images and colors, this scheme quickly breaks down as the scene has less variety.
One attempt to address the limited contrast ratio of current capture devices is through the use of a backlight feature. For instance, where there is a bright light source in the background, e.g., sunlight, backlight compensation will take the center of the scene and use that region as the average. By doing this, the center of the scene may be brightened while the bright sunlight on the edges becomes washed out or darkened. The shortcoming with backlight compensation is that the object to be brightened must be in the center of the scene. In addition, a region of the scene is used for computing the average, rather than the actual object itself, which may cause some display artifacts. Furthermore, backlight compensation does not provide a solution where there are multiple foreground images in different regions of the scene. Additionally, with backlight compensation, the foreground object is brightened, however, this is done at the expense of the detail in the background. Thus, a user is required to choose between foreground detail and background detail. Some of these shortcomings may be extended to video capture devices which may be used for interactive entertainment applications. For example, where an image of a user is incorporated into a video game, a bright light source may adversely the displayed image as described above. This adverse impact may prevent the tracking of an object of the image in addition to displaying a poor quality image.
Accordingly, there is a need to solve the problems of the prior art to provide a system and method for producing an image that has the exposure/gain and other related parameters adjusted for both the foreground and background.